Yes but it is not to be used just to keep your thread alive...Threads will keep themselves on top with good postings and good replies.
Bumping is usually refered to by those with dire needs to get help and have yet to find the answers to their problems. It is then ok to bump their thread in hopes to getting an answer instead of reposting the same question over and over..
This also allows others to read the posts in case their reply would duplicate another's.
This should be kept down to a minimum of 1 time a day or twice at the max if it is an extremely busy day and the posts are being archived rather fast.