I would never give access to my email account to a fly-by-night SAAS service. Nevermind the privacy concerns of mining my data, I just wouldnt trust their security practices unless they prove otherwise. An email nowadays is considered your identity. Any breaches to it can have a number of social, professional and financial implications.

Case in point, unroll.me mentioned in this article has a number of issues [1] [2] and response of Josh Rosenwald, founder of unroll.me at [3] dismisses that risk for perceived convenience.

[1] https://plus.google.com/u/0/+SimonPhipps/posts/fJQZbGuoY9G

[2] http://startup-stuttgart.de/unroll-me-complete-mail-data-tre...

[3] http://startup-stuttgart.de/unroll-me-complete-mail-data-tre...

P.S. previous discussion of unroll.me security hole: https://news.ycombinator.com/item?id=7035724