The best submission services help you to educate yourself. If you want to take over the submission duties in the future, you'll have a much shorter learning curve than if you just studied up from scratch. Simply enter your info, being careful to follow their submission rules to the letter, and you're off. An auto-submitter, which lets you enter your information just once and submits it to lots of search sites, can greatly reduce the tedium of submitting to sites one by one. However, some submitters swear by manual submission, as it lets you craft each entry more carefully.
Some people go off the deep end, and go spam-crazy.
I patiently explained to him that Yahoo will only list a site in two categories in any case, and that spamming in all those submissions might just annoy the worthy folks at Yahoo. To say nothing of how much I would charge him for such an endless and pointless task. Well, I found out what happened, all right. I've probably gotten an average of twenty spamograms a day since then. A word to the wise.