That's what I was thinking Dolphin, and wanted to take the opportunity to note that I think the reasons for doing this vary and are usually well-intentioned. The desire or "compulsion" to do so can be very strong; and also, while we shouldn't post to someone *expecting* to be thanked, I think it's also true that sometimes people hope to be, especially if to them a lot of feeling or effort went into what they said; or they want to get to know and are extending the hand of friendship to that person. (And hey, at least with thank-yous what everyone is sitting through is people "good-willing" towards each other! )

It is probably true that, especially for anyone who reads many threads, it isn't the most interesting reading, and I undertstand the distraction characterization. But if it is the person's own thread and they don't mind "risking" any of that, I think it's fine. Of course everyone should be aware of all their options and the benefits of each, such as waiting til the apparent end of the thread to thank everyone at once or PMing, and then they can decide which is right for them.

Now, maybe if someone does end up 'hijacking' themself and the actual subject gets changed, with their blessing or at their own initiation, options for those interested in the original subject might be just forging ahead with it (that probably couldn't be seen as hijacking); starting a different thread on it; or even just asking if it's ok to resume it, by posting to or PMing the originator. Especially if it seems to be genuine small talk at that point, rather than that the original poster addressing another aspect that also matters to them.

(Blah blah blah... I don't know why I always seem to be attracted to the principle and process stuff!)