just because this is a common case, i’ll post it for my own and public concern. this is the task:

show a text to contact the author of a page by (spamprotected) email if information to the author is found in the page object

temp.contact = COA
temp.contact {
50 = TEXT
50 {
value = {page:author}
insertData = 1
required = 1
typolink.title.dataWrap = {page:author}
typolink.parameter.dataWrap = {page:author_email}
noTrimWrap = |<div class="authorinfo">Could this page be improved? <br />(Pagetitle: {page:title})<br /><br />Please write to |</div>|
}
}