Conditional moves.

Is it poor gamemanship to initiate conditional moves when your opponent is still online and making moves quickly?

Not at all.  Arguably, you could be about to go offline or to become otherwise indisposed.  It's a means of allowing your opponent to continue to play without you having to be online.

Perhaps making better moves might prevent this.

No -- I can't think of a situation where it could be considered gamesmanship.  Nothing's actually preventing the player from ignoring your move and moving on to another game, and if they take it as a mocking of their gameplay then that's their hangup and nothing I'd worry about.

There's absolutely nothing wrong with it. I honestly can't even think of a reason that someone would be annoyed by it.

Agree totally, while remembering that on this site many people dont need a reason to get annoyed.

Conditional moves are not the same as pre-moves, not that I see anything wrong with either. A pre-move is a chancy thing, in case you miss a zwischenzug, for example. 

There's no reason to assume someone is doing computer analysis. Human analysis is enough to warrent conditional moves when looking at a forcing line.

In my mind they are good if they follow a one continuous line through the database, which I don't mind.

What I don't like is when you are on vacation, you come back and find a lot of games with conditional moves in them.

In response to pawnsolo2's original, I would say absolutely not.   Alekhine has a semi-famous quote about how a master must handle both the game and the clock as they are intertwined, and your commitment comes with a touch of risk.

While Zhane may not "like" that his adversaries work on the game while he's on vacation, they cannot control when their opponent (in this specific scenario, Zhane) moves or does not, and he has equal lee-way in this regard.  The implication that working on the game while one's adversary is not can somehow be construed as poor gamesmanship strikes me strongly as hollow.  All that can be reasonably deduced is that the adversary is up to the task of the competition.