I use lots "social webapps", I even revamped my planet today (I use Planet Noori as my RSS reader, but several people also read it, and a Planet has several advantages like the fact that it is easily reachable and readable by serveral devices like my cellphone with Opera Mini). But using third-party social apps have caveats.
My planet used to be on Ning, but it didn't give me the flexibility I needed, so I changed back to my own instalation and setup of PlanetPlanet.
Yesterday Google News was messed up, as well as Blogger was (that's why I didn't write anything here yesterday).
Merankorii's webshop (Merankorii is my musical project) was made using MyShopify: an AWSOME webapp to create an e-shop really easy. The problem is that it has a considerable downtime of several minutes per day. "Jaded Pixel does not warrant that the service will be uninterrupted, timely, secure, or error-free."
This isn't to be a big post talking about the Social Web, but simply aims to make YOU think.