Jakob Nielson posted an interesting article on
Transactional Email and Confirmation Messages.
In a Salesforce CRM context, this basically boils down to the subject and message contained within Web-to-Lead and Web-to-Case email auto-responders.
On the Lead side, I recommend a series of informative emails, aka an email drip campaign, that are conversational and informative in nature (even though Jacob advises against message sequences in an order shipping scenario, they are very effective when applied to Lead cultivation).
The email should appear as if it were sent from an actual person and not an automated response.
Example:
Subject: Follow-Up To Your Case Study Download
Hello {!Lead.FirstName},
Thank you for your interest in [product/service/organization]. I thought you may also be interested in the following resources:
Please feel free to reply to this email with any questions.Regards,
Personalized Signature
With complete contact information
For Web-to-Case, the best advice is to simply acknowledge receipt and describe what next steps are being taken to resolve the customer issue.
Subject: Support Ticket Received
Hello {!Contact.FirstName},
We received your trouble ticket. A service representative will review your case and respond within X hours.The following online resources may be useful in resolving your issue.
Notice both emails make use of bullets to break up the monotony of raw text and run-on paragraphs.
For case management, these links should also be published directly next to the web-to-case form to encourage self-service to FAQ'a and solutions prior to submitting a case.