It's widely acknowledged among Huffington Post alumni that founding editor Roy Sekoff ghost writes Arianna Huffington's columns. So it would be natural to expect Huffington to outsource her new Twitter stream, as well.
If Huffington were typing up her own entries, she'd probably be doing so from one of her beloved BlackBerrys. Instead the posts are coming from TweetDeck, an application available only on Macs and PCs (not the 'Berry).
Between that, the adroit use of URL shorteners (Huffington is not known among her staff as a particularly tech savvy Web mogul) and the distinct lack of typos, it seems a safe bet Huffington is running her Twitter stream through the same HuffPo editorial pipeline that producers her columns, books and TV talking points.