The ban has not been lifted, but sensibly, it's been suspended.
Barcelona were given a two-window ban from transferring in new players by FIFA due to cases involving the transfer of U18 players.
The front office submitted an appeal that argued that the minors were taken care of correctly, and thus, the ban was unfair. While FIFA has not accepted this argument, they are suspending the ban pending a final decision.
Such a suspension is entirely logical. If Barcelona were banned for two windows, and then FIFA realized they did not break any rules, the punishment would have already been served. In other words, if Barcelona were found to be innocent, it wouldn't matter - they would have already been punished.
That's why delaying punishment until the appeal had gone through makes sense for the moment.
Speculating here, but I think that while Barcelona did in fact break the letter of the law, they probably did not break the spirit of the law - at least, not to a large extent. Such extenuating circumstances probably mean the punishment will be less severe than originally conceived, though it'd be foolish to assume no punishment would be forthcoming at all.
This means that this window should be a seen as a key time to make big moves, because Barcelona may be limited in the future.
There are two problems with this - one, it's a World Cup summer and that can inflate prices and create a distraction that slows down deals.
Second, it means Barcelona have to pull the trigger now even if the deal is not optimal - they can't wait another window to see if there are better options available then.
With that said, Barcelona don't have much of a choice.
Marc-Andre Ter Stegen is near-certainty to join Barcelona, despite official denial that it's a done deal. The Gladbach keeper would take over for Victor Valdes as starter.
Assuming Valdes nor Jose Manuel Pinto remain in the squad, a backup keeper is a priority. Barcelona could move for an experienced backup like Keylor Navas from Levante, or they could go bet on the kids - Oier Olazabal, currently the primary backup with Valdes injured, or Jordi Masip, who starts for Barcelona B.
With Carles Puyol's exit confirmed by the player, Barcelona need at least one new centerback. That is the deal that needs to be given the most priority. A second defender may be needed if Javier Mascherano were heading out, or if he were to be re-converted back to defensive midfield.
I suspect Dani Alves will remain with the team and no new fullbacks will be brought in. However, it would be good to get started on a list of potential replacements, just in case.
In the holding midfield role, Alex Song is rumored to be leaving. Again, Mascherano could be his replacement, otherwise a new signing may be in the cards. It's unlikely Jonathan Dos Santos will be trusted enough to be a primary rotation option, and Sergi Samper is still a bit too green despite his wonderful potential. Sergio Busquets will remain the unquestioned starter.
When it comes to attacking midfield, Andres Iniesta, Xavi, and Cesc Fabregas are all likely to stay. There have been murmurs of an exit when it comes to the latter two, but unless that happens, making a big signing will be of lower priority. Already, the team sealed a deal with Croatian wonderkid Alen Halilovic for the B team. Rafinha Alcantara could return after a successful loan spell with Celta. Denis Suarez is a potential B team promotion, while Sergi Roberto may be on his way out, possibly on loan.
In the winger spots, Neymar is a guarantee next season but, after that, the picture is murky. Alexis Sanchez is rumored with a move back to Italy seemingly every year. If not, Pedro Rodriguez is rumored to be on his way. Cristian Tello's diminishing appearances suggest he may be sold, possibly to Liverpool, but it will likely depend on the judgement of the coach - whoever that is come next season.
Marco Reus is the big name attached to Barcelona, and why not? He's popular, talented, and a Barca fan.
Vamos barca— Marco Reus (@woodyinho) January 25, 2012
However, the picture seems full unless someone departs. The same could be said for Gerard Deulofeu's possible return from loan.
Upfront, the search for a striker remains. Of course, despite the rumors, it's pretty unlikely Lionel Messi would go this season. Sergio Aguero is perhaps the sexiest name in a big, big list, but chances are that if a player of this profile is signed - and that will depend on the coach - that it will be a smaller name but a bigger frame.
We are looking at two sure signings, plus one mandatory (CB). On the other hand, the high estimate would add an additional 4-6 players to the 3 already mentioned. If there was a time to make a move, that time is this window for Barcelona. Who knows what comes next.