The July issue of Silverpop's newsletter "The Digital Marketer" featured an article called "Eight Easy Ways to Boost Email Deliverability".

One of the tips is this one:

Avoid spammy gimmicks: your email shouldn’t resemble a bad Las Vegas lounge act. Spam filters seek patterns and irregularities often found in spam, so resist the temptation to spice up messages with all-caps, big fonts, weird punctuation, exclamation points, repeated phrases, or common advertising come-ons such as “free!” or “limited time offer!”.

It’s also a good idea to screen your messages with a spam filter such as SpamAssassin to flag any potential content problems before you send. The other seven ways ways to boost email deliverability are these:

• Never send commercial email to people who haven’t consented to receive it
• Practice good list hygiene
• Don’t ignore ISPs
• Keep volume low
• Protect your corporate IP address
• Implement authentication protocols
• Consider an Email Service Provider

Read the full article here.