Hi,
you can customize titles by creating a translation for your language (or edit english language). see docs about this at http://docs.easy-profile.com/index.php/article/social-network-make-your-language

I do not wish to change to any language, just want to change the heading of "Topics" into "interests"

You can only change english language:
- Open file /plugins/jsn/socialnetwork/app/Locale/en_GB/LC_MESSAGES/default.po
- Add your translation at line 329, now it is empty
- Clean Global Cache (docs at http://docs.easy-profile.com/index.php/article/social-network-make-your-language)

Hi,
I would like to change this as well, but ONLY the term "topics" in the main menu. Is this possible?

Hi,
sorry for late, today we are very busy

I think that I do not understand well your question, because the solution for your problem seems the same above

You can only change english language:
- Open file /plugins/jsn/socialnetwork/app/Locale/en_GB/LC_MESSAGES/default.po
- Add your translation at line 329, now it is empty
- Clean Global Cache (docs at http://docs.easy-profile.com/index.php/article/social-network-make-your-language)

Hi, I would like to change "Topics" in the main menu to "Forum". And leave all others submenu's with "topics" untouched.

ok,

this is not so simple, because Topics is a common language string (used in different parts of plugin).
The most simplest way is to change plugin name from DB:
With some tools like PhpMyAdmin (offered from many host provider) you need to change from "Topics" to "Forum" the column called "name" from table "#__jsnsocial_plugins"