Testing Browser-based Email Services

You might want to setup accounts with all the browser-based email services. They’re
usually free, so it’s easy to setup lots of test accounts. You especially want to look at
how browser based email services alter your HTML and CSS.
Also, since these services are used by bazillions of people, their anti-spam filters are set
really high. We listed them below in order of most-to-least popularity (according to a
recent survey across all MailChimp managed lists). When you setup your test accounts
with these services, leave their “junk mail filter” settings to “default.” It really pays to test
on these accounts before sending your campaign...
Yahoo!Mail
Pretty aggressive anti-spam filters (understandably). Other than that, they do the typical
browser-based email stuff, like stripping your BODY and HEAD tags.
Yahoo!Mail Beta
A much richer browser interface, with a preview pane. So far, support for HTML email
looks great.
Hotmail
Similar issues as Yahoo!Mail, where BODY and HEAD tags are stripped, so background
colors and embedded CSS are lost. At one time, Hotmail was “expiring” hyperlinks in
emails that were open for 5 minutes or longer.
Gmail