Filckr is offering three months of its Pro service for free as a "holiday gift" to new and existing members.
It's not a hugely expensive gift on an individual basis: the Pro service costs just about $25 per year, or a bit less than $2.10 a month (or about $45/year and about $1.88/month). But it gives users a nothing-to-lose chance to try Pro, which offers among other things unlimited uploads (of up to 50MB per photo), unlimited viewing of one's entire uploaded library, the ability to download one's original high-rez photos, and ad-free viewing of Flickr.
As noted by CNET's Declan McCullagh, Flickr has been among the Instagram rivals trying to capitalize on the latter service's blunder earlier this week, which saw it spark a user revolt by changing its terms of service and saying it had the right to sell user photos to advertisers. During the kerfuffle, Flickr parent Yahoo pointed to a Flickr post titled "At Flickr, your photos are always yours." Instagram has since issued a mea culpa and backtracked on the change.
Flickr has also recently released an overhauled iPhone app, which grabbed four out of five stars from CNET's Reviews team. Flickr, an old-timer on the Web, remains relevant, with 85 million active users per day.