In light of TonyRo's question, I will assume this is a re-design of subscription part of ChessPub.
I will out myself as a lapsed subscriber who is only a novice sub-2000 rated player with an inordinate unhealthy fascination with opening theory blessed unfortunately with a very leaky memory.
Seriously, Tony, if you wish to attract more subscribers (and I assume this as a basis for this post), I think you need to make it more user friendly. The majority of chess players in the world are club-level sub-2200 rated players. I think (and here I might be overgeneralising) they may be interested in compact succinct easy-to-learn opening repertoires. At present, I think the existing e-books and pdf-books, whilst excellent, are a bit unwieldy. They are designed like a reference tome. Need to make them more user friendly. Distilling from my years of lurking on the Pub, reading tons f chess book and my educational background, my humble suggestions:
In line with another thread (
http://www.chesspub.com/cgi-bin/yabb2/YaBB.pl?num=1382573395)and a suggestion by Matemax on the usefulness of material/resources on/behind an opening, how about combining that with what Chess Stars are doing (there is no copyright in ideas), i.e. their quick repertoire. Also, how about adding to the mix, ideas from books like Sicilian Attacks, where the standard tactical themes et al, positional considerations are considered. But make them opening specific.
So, perhaps something like this:
1) Sicilian GP (just as a totally random example) Introd/historical - 2 f4 vs 2 Nc3 3 f4
2) Strategic aims - exchanging light-sq bishop on c6 for a doubled-up pawns? (sorry I did say I am only a novice and making this up based on what I see my friend plays in a GPA)
attack K-side? pawn storm hacking style? Q-side?
Knight manoeuvres?
3) Tactical themes/ideas
4) Endgames - any typical endgames
5) Opening theory
6) Complete games annotated
This is like a template but does not mean each field has to be filled with stuff. depends on the opening/var.
Important this is simple, succinct, short. A subscriber can learn this in 1-2 hours, go an delay a few games OTB, online etc and come back to check ideas, theory.
Also make these modular (which means you can actually drill down to Variations level as well) so that subscribers can chop and change their openings in their repertoire. Perhaps have a few suggested repertoires with different themes (the ones on ChessPub is really old and not that interesting). One that I found interesting reading here on the Pub as well as from Lars Bo Hansen's book is based on strategic ideas, i.e. his mixing of French Winawer with Ragozin 'cos of Bb4 move.
There is also the Qa5 Scandi with the Triangle based on the c6 and e6 pawns clamp.
If you like, you can make these as part of special member package for an additional one-off payment. Since they are modular, you can charge them using iTunes method, i.e., 1.99 or 2.99 per module.
I would suggest continue to maintain the existing pdf/e-book reference on theory as additional for a subscriber who has gone past the initial stage of learning the opening.
PM me if you wish to discuss.