A couple of tips on Craigslist listings:

1. Put the size in the title of the listing.
2. Also, add a rough estimate of the height of the riders it would fit (a range will do)

...so many noobs on Craiglist, so many bikes -- yours will stand out just with that info. Also saves a lot of emails.

3. Put the MSRP of the bike when it was new and the current MSRP of the current model in the ad.