It's a question that is often asked. Should there be as few as were on the marketing email or is now the time to try and convince by overwhelming the subscriber with facts? The answer is simple enough. As in most things to do with email marketing, there is no optimum; it depends.
I've recently received a marketing email that had 274 words on the landing page and I think it was just about the right number – for me that is. It was for a computer component, a motherboard. It was easy enough to see the company's logic. Technical specs. are vital information with such an item and most purchasers would peruse the technical details closely. All the vital ones were on the landing page, together with click-throughs to 'further information. A nerd's dream.
The image was very similar to the one on the marketing email, but then even I will admit that when you've seen one motherboard, you've seen them all. That doesn't mean, of course, that 274 words is what you should aim for. The company's information on me predicted precisely what I would want, and it was delivered. If they were 
selling socks it would have been different.
One way of ensuring you include as much as necessary, and no more, is to write out the headings for what information you wish to convey on the landing page. Prioritise them. Despite us having more time on a landing page to get our message across, it is important to hit the reader early with your major selling point, which you probably mentioned in the marketing email. If you said it comes in any colour, then on the landing page ask them immediately ‘What Colour do you Need?’.
Follow up immediately with the second point and then it’s time to consider what words are essential out of the rest of the headings you came up with. An epicyclic trunnion, for instance, will appeal to different people for different reasons, and you would have split your email marketing list accordingly. If one or more of the headings would not interest one group, ignore them.
Your intent is to make the decision to buy easier for your subscriber. Overwhelming them with data is not necessarily the way to go. For a technical item, such as the motherboard, being all teccy works on a number of levels, the most important being the company shows it knows what it is talking about and so can be trusted. It went a little further on my one. By allowing click-throughs to further information it became more inclusive.
It’s a truism; know your subscribers. It should be easier for us as we are not making instant decisions on customers as they walk towards your counter. Ask yourself what they need to know and what will convince them to convert and ensure both are covered in the copy. Everything else is superfluous and probably a bit self-indulgent.
In fact, it’s not a bad motto for life; show what you need to show, and no more.
