per this NYT article, he and Romney have been accused but both have said they didn’t:
“Fake Twitter followers briefly made the news in July, when Mitt Romneys Twitter following jumped by more than 100,000 in one weekend a much faster rate than usual. A flurry of news reports purported to expose the practice of buying followers. Romney Twitter account gets upsurge in fake followers, but from where? read a headline on the NBC News Technolog blog. (The Romney campaign has denied it bought followers.) Similar claims were lobbed at Newt Gingrich last year; his campaign also denied that he paid for any of his 1.3 million-strong Twitter following.”
http://www.nytimes.com/2012/08/23/fashion/twitter-followers-for-sale.html?_r=0
I thought I remembered that