More mass email thoughts

This is an edited version of an email I sent to a client today who asked about subject line guidelines for mass email:

• Avoid obviously spammy language: save, business, bargain, etc.
• Avoid bogus spellings and ways around the language issue, i.e. V_I_A_G_R_A. Shouldn't be an issue for any of my clients.
• Shorter is better but long isn't necessarily a deal-breaker. I'd keep it under 20 words.
• Personalized is better ("Mike, this week we're offering a friends and family rate at The Peaks and Golden Door Spa in Telluride"). Z-Com can do this if you're interested. 
• A clear, direct offer is better -- for example, you're not really offering anything special in your current subject line. What's the value proposition? Example: check out my sample personalized subject line above.
• Set a time limit and create urgency. Again, see my sample subject line.

Anyway, just some thoughts for those of you thinking about doing a mass email campaign.