Paul doesn’t just spend a lot of time in 1 and 2 Thessalonians talking about his parousia but also about the parousia, the second coming of Christ. There was certainly an element of eschatological hope underpinning the gospel the Thessalonians are said to have accepted – but Paul’s main concern seems to be putting those expectations in their right place.
Ben Witherington III (or BW3 as Tamie called him in the comments the other day) suggests the word parousia often had royal significance, he notes that Christ’s parousia is mentioned six times in the letters to the Thessalonians – he suggests Paul is co-opting the imperial terminology here and applying it to Christ.
Paul’s view of Christ’s parousia involves him descending from heaven and the dead rising – it is eschatological. BW3, and BW1 (Bruce Winter) both think that the talk about the second coming is to help comfort the bereaved. Bruce argues that food shortages and earthquakes had been taking a toll, and that this had caused a heightened eschatological anxiety. BW3 says the hope of heaven, and the second coming, was part of that healing process. Especially in 1 Thessalonians 4-5. Which he says (I should mention this is in his socio-rhetorical commentary on 1-2 Thessalonians) in verses 14-16 are about reassuring the Thessalonians that their dead loved ones will take part in the parousia event.
2 Thessalonians 2:1-12 makes the Imperial context clear – if the son of lawlessness is understood to represent the Roman Imperial Cult, and the Emperors who turn themselves into gods. It also draws a direct contrast between Jesus’ parousia, and that of the emperor.
Dunn says that Thessalonians is dominated by the parousia like no other Pauline writings – and suggests that 1&2 Thessalonians are amongst his earliest letters (implicitly suggesting that Paul got over this phase), he also (like BW3) points out that the parousia will bring relief from the Thessalonian’s present sufferings (at the hands of lawless men). Paul was concerned that they know the day of the Lord had not arrived already, which some had suggested, but that they’d know it if they saw it. He says that it’s clear Paul was addressing a particular concern of the Thessalonians here that didn’t come up elsewhere. Paul was not surprised, as the Thessalonians were, that some of them had died. And the dead were to share in the benefits of the kingdom too.
Here are some related paragraphs regarding the Imperial Cult in Thessalonica from the same extended edition of an essay that I used for the Galatians post (read: this is the stuff that got deleted from the final version so I’m just happy to be using it). He says that it is particularly in cases where Paul speaks eschatologically that imperial terminology crops up.
Harrison (2002) suggests Thessalonica was enraptured with the ‘imperial gospel’, whose ‘eschatology’ proclaimed that Augustus had arrived as the ultimate Saviour, and that Paul writes to radically subvert this idea. He suggests use of κυριο without deference to Rome was inconceivable.
Numismatic and epigraphic evidence support the notion of a flourishing imperial cult in the city. Its citizens are zealous for the emperor. The accusation brought against Jason and his fellow Christians in Thessalonica (Acts 17:5-7) is that they preach a different emperor. Judge (1971) suggests this charge arises from an oath of fealty the Thessalonians swore to the emperor as part of their cultic practices. Donfried (1997) suggests Christians in Thessalonica had been martyred at the time of Paul’s epistle, for breaking this oath.
Paul believes the Thessalonians to have given up on idol worship (1 Thess 1:9), which included the deified Caesars. Donfried suggests the calling of the Christians into God’s own kingdom (1 Thess. 2:12), and παρουσία, απάντηση (1 Thess. 4.15-17) has imperial undertones, Harrison agrees, drawing on the use of the Latin equivalent of παρουσια on imperial coinage to support this view, Oakes suggests the use of παρουσια, in this case, has no imperial significance,  but agrees with both that the use of the shorthand form of an imperial slogan (1 Thess. 5.3), was deliberate. 
 Oakes, P, p 306, Harrison, ‘Paul and the Imperial Gospel at Thessoloniki,’ JSNT 25 1, 2002, pp 71-96, Harrison suggests 1 Thess 4:13-5:11 is a deliberate and provocative reimagining of Augustan eschatology, post death Augustus is believed to rule the world from heaven via his star sign, maintaining the political status quo. Paul’s contrast of a king who will return from death is couched in imperial terminology and could not fail to be understood that way.
 Harrison, J.R, p 78
 Harrison, J.R, ‘Paul and the Imperial Gospel at Thessoloniki,’ p 81, “The obverse of a series of Thessalonian coins show the laureate head of Caesar and carry the legend ΘΕΟΣ. The reverse displays the bare head of Octavian either with the legend ΘΕΣΣΑΛΟΝΙΚΕΩΝ or ΘΕ|ΣΕΒΑΣΤΟΥ”
 Judge, E.A, ‘The Decrees of Caesar at Thessalonica,’ The First Christians in the Roman World: Augustan and New Testament Essays, ed. Harrison, J.R, (Tubingen: Mohr Siebeck), pp 456-462, orig 1971, the oath (CIL II172) the people of Antium swore to Caligula thirteen years before Thessalonians was written reads: “On my conscience, I shall be an enemy of those persons whom I know to be enemies of Gaius Caesar Germanicus, and if anyone imperils or shall imperil him or his safety by arms or by civil war I shall not cease to hunt him down by land and by sea, until he pays the penalty to Caesar in full I shall not hold myself or my children dearer than his safety and I shall consider as my enemies those persons who are hostile to him If consciously I swear falsely or am proved false may Jupiter Optimus Maximus and the deified Augustus and all the other immortal gods punish me and my children with loss of country, safety, and all my fortune.
 Donfried, K.P, ‘The Imperial Cults and Political Conflict in 1 Thessalonians,’ Paul and Empire, ed Horsley, R.A, pp 221-223
 Oakes, P, p 309
 Donfried, K.P, ‘The Imperial Cults and Political Conflict in 1 Thessalonians,’ Paul and Empire, pp 215-216
 Harrison, J.R, ‘Paul and the Imperial Gospel at Thessoloniki,’ JSNT 25 1, 2002, pp 71-96, p 81, 83
 Oakes, P, p 315, though it was common terminology that described an arriving political leader
 Oakes, P, p 318, Harrison, p 86-87