when you want to sell a bike that's worth a few grand,
The asking price is one thing that's really wrong with the ad, $1K looks to be about the going price for a used 2008 Stumpjumper FSR Comp.
http://www.ebay.com.au/itm/281053880812?
http://www.ebay.com.au/itm/190795391117?
it's a highly unusual to offer no real description of the item. Could be the owner's uncle selling it for him while they're overseas.
There's ads with poor titles and descriptions all of the time, it doesn't automatically make them stolen. The situation you've listed could be right or
Jenny (the seller) might of broke up with her boyfriend who owed her some money, he might of said take my bike and sell it it's worth a couple of grand (even though it isn't) .
There's a good strike rate on here of people helping eachother find their stolen bikes, and it's the main reason I'd defend the actions of the OP in posting the suss item. If no-one recognises it, it'll fade into history, ain't nobody gonna be lynching the seller for being suss.
There ain't that good a strike rate in getting stolen bikes back, if I see a dodgy bike ad I'll do a google site search for a couple of forums to see if anything comes up.
I found nzhumpy's
Stolen Yeti 575 for sale on gumtree about 16 months ago, he got the bike back.
There's two things about the ad in question that makes me think that it's not stolen is.
1) thieves don't give out the address where they live
2) thieves put low prices on things so they sell quick
If someone contacts the seller then a bit more info might be found out about the bike.
More info might lead to less speculation.