I would never think of building a tire to use on my car, I’d buy one that is refined, tested and works! So why do so many developers insist in re-inventing the wheel?
I was talking to a Developer recently who wanted to build a mass emailing system to add value to their CRM product. Rather than building from scratch and having to become an expert in the world of email marketing, tracking, spam, and the best practices in that area I suggested looking at integrating a 3rd party email marketing software.
The benefit of taking something that is already refined and feature rich is a quicker time to market, less to develop and maintain (and is improved constantly for you). Additionally, you can often find nuggets that are worth drawing back into your existing systems to improve additional functionality – such as the Member Rating from MailChimp.