I grew up in a shul which had the standard, twentieth century, heavy metal yahrtzeit board, with heavy plaques attached. The plaques were flanked by sockets for small incandescent light bulbs, which flickered constantly. You can see models here.
At some point, though, my shul (Young Israel of Oceanside) made the leap to a new form of board: Custom-made wood boards, finished to match the shul's décor, on which the plaques were attached. Instead of sockets for individual incandescent bulbs, one vertical flourescent bulb lined each column, behind the board, and each plate was flanked by holes which could be sealed (ie off) or left open (ie on).
The leap from the first model to the second makes a lot of sense, solving many problems:
1. The old metal boards are incredibly heavy, requiring strong walls and serious anchoring;
2. The bulbs on the old boards flickered because their contacts were supposed to hit a metal plate which conducted electricity behind the boards. Over the years of having the bulbs screwed in or unscrewed for yahrtzeits or yizkor or just by children who played with them, the contacts eroded, so that they didn't reach the metal plate well;
3. The old boards are incredibly expensive;
4. The old boards are very dated, in their appearance.
Why don't all shuls switch to similar newer, cheaper, more effective memorial boards? Largely because they already have multiple old boards. Members don't want the new boards to look different. Members don't want the new ones to look less expensive. Members don't want to have change, in general.
In truth, my shul in Allentown went even further. When it came time to add a board, we revamped the system altogether. At the impetus of a particular member who took this on as a personal project for the shul, we set up a digital picture frame showing a digital nameplate plaque. On a given day, the picture frame scrolls through all of the plaques for the day's yahrtzeits. On a yizkor day, the frame scrolls through all of the plaques.
Aside from solving the problem of running out of space, anchoring new boards, affording new boards and so on, this also made my job easier. Standard boards require that someone go through them every few days, turning bulbs on or uncovering spots for upcoming yahrtzeits and turning the bulbs off or covering up spots for yahrtzeits which have passed. Now, it's all automated, using databases to regulate what will be displayed, and when. The only regular adjustment is the display's on/off time, to make sure it is operational when people come for minyan in the evenings.
I admit that I was disturbed, at first, by the possibility that people who had memorialized their loved ones in the old system might not see this new method of display as adequate; after all, we had contracted to light bulbs next to their plaques, not to use this newfangled system. But people were very comfortable with it, and so we went with it.
This is what a digital plaque looks like:

Of course, the new system did raise a different question – If we can have a digital screen in operation on Shabbos and Yom Tov, what about having a running ticker with the sports scores…