Can I use the letters and cards I receive from my clients on my website without their permission?
Rhetorically, why would you want to publish thank you letters without your client's permission? By using the letter, you are now turning a private conversation into a public endorsement. There is a big difference between those. By publishing them without permission, you may:
- Tell the public about your private relationship;
- Expose a communication where the other person may have had a social expectation of privacy;
- Potentially reveal your client's confidential information; and
- May make your client upset.
Any of these may cause you to lose your client.
On the other hand, if you ask for your client's permission to publish, you will further honor your client by respecting them and valuing their relationship. Also, if a website-visitor directly contacts your client after reading your client's letter, then your client will be prepared for that sort of contact (and not surprised).
Given all the advantages and disadvantages, why not just get permission? It is easy to do, just ask. Follow up with a short email or letter.
This is not legal advice, just information about good business practices. To provide legal advice, there must be sufficient information about the actual facts to properly apply the law to a situation. As always, check the information that you find on the Internet against primary sources, such as your own attorney.