A call to action is an advertising and marketing concept, a request/direction to ‘do something’—often the next step that a consumer could take toward the purchase of a product or service.
“A call to action answers the [unspoken] question, ‘That’s interesting. Now what?” 
In real world media (print, radio, TV, etc.), example calls to action include:
Translating the concept of a call to action to online marketing and copy writing has proven problematic as the boundaries between marketing and fulfillment are blurred. A website may both promote, and enable a user to purchase, a product or service.
…buttons in a lift do not feature the text ‘push for…’
Unfamiliarity with the semantics of the medium has led to copywriters appending the phrase ‘click here’ to link text. The ‘click here’ is redundant (unless the presentation of the link does not effectively communicate its click-ability).
As an analogy, buttons in a lift do not feature the text ‘push for’. A less generous comparison might be made between ‘click here’ in hyperlinks and used-car dealerships signage: ‘LOOK: low mileage, easy payment terms…’.
The addition of ‘click here’ to hyperlink text also necessitates a less-than-optimal sentence structure. Either the reader must re-read the surrounding text to establish the link destination:
[A] To view our entire catalogue click here;
or the link text must include both the ‘click here’ and destination description:
Neither of the above link texts supports scanning. In example [A] one ‘click here’ is indistinguishable from another, in example [B] the words that identify the destination content (trigger words) are to the end of the link text, this is less-effective as the eye naturally gravitates to the beginning of the link.
One instance where ‘click here’ is appropriate, is when click-ability is not communicated by an appropriate visual treatment. This may be the case with advertising images (banner ads).
Navigation and content structure can be used to provide a non-invasive call to action. For example, under each of the Motive Glossary entries, links are provided that support likely next steps.
|Scenario/next step||Supporting navigation|
|“I’m still not sure I‘ve understood this term/I’d like to understand more about this term in context.”||Related terms|
|“You’ve piqued my interest, where can I find out more?”||References and further reading (list)|
|“I’m interested in finding out about another term.”||Glossary index|
|“The glossary does not include the term I’m interested in.”||Suggest/request a term|
|“I’m at a loss.”||Glossary trivia (lists): New additions, Popular, Recently viewed.|
|“I’d like to link to this glossary entry.”||Link Policy (footer navigation)|
Incidentally, 10-15% of the glossary entries viewed are linked to via the glossary trivia lists.