Sure, there’s a couple ways to do it.
If you want to turn off linking in specific profile fields (so that nothing in “About Me” gets linked, but locations in “Location” or “Hometown” do), you can use http://wordpress.org/extend/plugins/custom-profile-filters-for-buddypress/. Near the beginning of that plugin, there’s a spot for you to list fields that should NOT be linkable.
If you want to be more specific and look for certain words in a field, here’s how. Copy the original xprofile_filter_link_profile_data function from bp-xprofile-filters.php, paste it into functions.php or wherever you put the remove_filter code, rename it something unique (like henry_xprofile_filter_link_profile_data), then afterwards add the line
add_filter( 'bp_get_the_profile_field_value', 'henry_xprofile_filter_link_profile_data', 2, 2 );
At this point you’ll have to customize the filter to look for certain words. Use something like this (untested, but something like it should work):
if ( strpos( $field_value, 'Boston' ) ) {
$field_value = str_replace( 'Boston', '<a href="' . site_url( BP_MEMBERS_SLUG ) . '/?s=Boston">', $field_value);
}
In other words, if ‘Boston’ is found in the field, replace the plaintext ‘Boston’ with a link to a search on the word ‘Boston’.
