Publishing on arXiv effect online scholarly profile
Both Google Scholar and CiteSeerX can detect arXiv publications.  I know for certain on Google Scholar because it has detected mine (and it is also adding to my H-index on the site).  For CiteSeerX, if you search by publication venue, you will find many publications in arXiv.  Both systems will, however, attempt to merge versions (and Google Scholar at least allows a person to do this manually as well), so a subsequent journal publication can supersede the arXiv version, making such an arXiv version apparently invisible even if it is part of the profile and collecting citations.

Neither system makes any guarantees, however, about how quickly it will detect papers in particular venues, so it is possible that arXiv is updated less frequently or more erratically than others (particularly for CiteSeerX, which is often plagued by maintenance issues).