I think it really depends on the products... If you are talking about simple web apps with quick development times and maintenance, I see no problem attacking

I think it really depends on the products... If you are talking about simple web apps with quick development times and maintenance, I see no problem attacking with multiple products simultaneously. But the down side is, most quickly developed apps require a critical mass quickly (and to get there quickly you need to market and get the word out, which you need time). The other downside is their easy to be cloned by someone before reaching critical mass (due to quick dev time). Now if you're building a bit more involved project with complex development, high server requirements, or needs users to put a lot of trust in your system, I would highly suggest deviating attention away from it.