The two tools above function based on the same principles: you insert your URL, choose the services you want to ping and click “start ping.”
In a matter of seconds the news about your updates reaches Technorati, FeedBurner, My Yahoo!, Sindic8, NewsGator and so on. This will send traffic to your blog and it will help with your linking strategies.
While Ping-O-Matic has a simpler user interface, Autopinger offers the advantage of a “set-and-forget” tool, which is particularly helpful for blogger blogs.
The SEO value comes from the sites that will really pick up and index your links (Technorati. Weblogs, FeedBurner, etc.) Autopinger is particularly beneficial for blogger and MSN Space bloggers. Blogger pings only weblogs.com.
As far as MSN is concerned, you have to ping it manually by submitting your feed. Ping-O-Matic is not bad either, but requires manual pinging every time you update your blog.
As its name insinuates, Autopinger does the job automatically. A manual pinging option is available too, for the users who don’t like subscribing at too many services. The good news is that Autopinger works for podcasts too. So if you ever stumble upon a SEO company that promises you to submit your blog or podcast to the most important blog search engines for a certain monthly fee, think twice. They are going to use these free, automate, tools. Are you really going to pay for something you could do yourself?