We only archive FT Miles currently. Although Travel has been growing steadily, we don't think it's at a point yet to cause trouble. Also, the archive system is actually just another license of FlyerTalk, where we try and match up forum numbers from FT Miles to their corresponding ones in FT Archive. If we're to start adding Travel (and later possibly Dining and Airport) threads, we'll have to add another license or find some other way to keep the forum numbers consistent.