Update, 10:55 p.m.: Here's a useful lesson for those hoping to drive messaging on Twitter. The Romney campaign tried repeatedly to get #webuiltit to take off. But #IStandWithAnn, championed by a user with fewer than 1,000 followers, easily surpassed the campaign's synthetic viral campaign.
In an effort that appears highly coordinated, tweets from Mitt Romney, Ann Romney and Paul Ryan all began using the hashtag #WeBuiltIt Tuesday evening ahead of Ann Romney's convention speech tonight. Hundreds of retweets propelled the tag to 450 mentions in a 15-minute period, the peak thus far.
The earliest instance of this hashtag that we can locate came from user @Tom_Shotz a week ago, but there is no apparent connection. It will be interesting to watch whether this sort of top-down hashtag generation from the campaign catches on widely.
Update, 6:56 p.m.: Yahoo News' Laura Davis points out that the campaign paid to promote a tweet with this hashtag as well.