I asked my Twitter followers to finish the sentence "Email marketing works because..." today. Here are some of the responses I got:

• @marcmunier: Email marketing works because people spend more time at their inbox than any other online activity
• @adrianragucos: email marketing works because, honestly, who does not use email these days?
• @MarkatEMR: Email marketing works because emails deliver value to gain attention at the heart of the online world: the inbox
• @spamtacularcom: Email marketing works because of trust between the sender and the recipient.
• @siherron: Email marketing works because it's malleable, measurable and cost effective
• @DanniEmery: Email marketing works because it enables you to send targeted messages and see instant measurable results
• @newzapp: Email marketing works because it's affordable, flexible, can be targeted and tracked
• @djwaldow: "Email Mktg works b/c it has a proven, measurable, ROI; easy to test; "Long" track record; digital glue of SM
• @stefaneyram: Email works because it is measurable and can be easily tested and optimized.
• @jewelss: bc it's cost-effective & allows u to form a personal relationship w/ a consumer by way of their inbox! :)
• @RupertHarrison: Email marketing works because... it allows you to send your customers what they want, when they want it
• @mbagrrl: Email marketing works because..." you are reaching customers who have opted in and you know are interested in your comm
• @adRom: email marketing works, because you know the recipients.
• @Newsmarketing: Email marketing works because there is still a lot to discover with this channel...
• @resultsrev: Email marketing works because mainstream tech adopters are still leaning heavily on their Inbox
• @resultsrev: Email marketing works because there is no gatekeeper. Viral potential.
• @Newsmarketing: Email marketing works because it is (still) communication media Nr 1 in the world
• @PhilMonk09: "Email marketing works because it's extremely cost effective"
• @KNLorenz: Email Mkting works b/c it's a 1-to-1 comm. (ideally) & email ties most online activities together-purchases thru personal
• @DocS: Email marketing works because I know my followers better and I can select, target, test and measure
• @eWayDirect: when it's the right message delivered to the right person at the right time in the right way
• @LorenMcDonald: Email marketing works because when done correctly no marketing comms channel resonates more w/ subscribers & delivers higher ROI
• @thecmunzproject: Email marketing works because it opens up a conversation that otherwise you could not have with your members.
• @messagingtimes: Email marketing works because it facilitates direct, relevant and measurable conversations with people.
• @djwaldow: Email Marketing works b/c unlike other social media tools, nearly everyone uses (& regularly checks) email. Even my dad.
• @DaveMcCue: Email marketing works because doing it right places a premium on audience satisfaction.
• @tomwyns: because it is a cost effective tool to spread your message instantly and directly towards your readers
• @resultsrev: Email marketing works because I test & measure subject lines & content that can then translate to other media
• @tabsharani: Email Marketing works b/c it has a a proven track record & has become a "natural" way of conducting business.
• @simmsjenkins: Email Marketing works b/c your customers & prospects asked for it
• @jordancohenpr: Email marketing works b/c you learn something new about your brand and customers with every mssg you send
• @spinnakerpro: email marketing works because email, as the most widely used web application, builds lasting relationships
• @LukeAnker: Email marketing works because it shows you care for your prospects and customers and they appreciate this
• @flatironsi: Email marketing works because email is the backbone of permission-based, digital communication channels.

and my personal favorites:

• @adrianjock: Email marketing works. U'll know that it stopped working when the spam disappears LOL
• @emailtransmit: Email Marketing works b/c you can prove that it does.

Feel free to re-tweet these responses :-) I'll update this post with new responses as they come in...