Very few solo, self-funded, consumer-focused SaaS products go anywhere. The number is very close to zero. So it may be a great idea, but it's very hard to get a user base and then monetize it enough to cover your costs.

For this particular concept, I just think most people are using only one social network. The people who are on many are probably power users, and they'll mostly be interested in publishing (e.g. HootSuite).