The blog is a personal touch - use profanity if you think the people it attracts will buy your sh*t.
Sorry - had to do that! What is the purpose of profanity? Will it help you sell? Then by all means be vulgar!
In most cases profanity is unnecessary.
If you are selling crap to outlaw bikers, it might help. If the so-called profanity is part of the description, then we are dealing with censorship. In that matter Ebay always wins - Ebay censors all kinds of crap.