Since IBM acquired Informix there has always been the question of how Informix was positioned versus DB2. The answer that IBM has promulgated has been that Informix was IBM's offering to support embedded applications where you could fire up the database and forget about it because it essentially needs no administration. In other words, Informix has primarily been targeted at ISVs and software houses that were developing appropriate applications. Of course, this didn't preclude direct sales of Informix but this was the main thrust of IBM's marketing.
This has now changed, with the emergence of instrumented (breakthrough) applications offering new opportunities for Informix. In particular, IBM is targeting time-series based applications with Informix. There are many instrumented environments where data is time-stamped and it is important to understand the sequence in which data is collected. An example is smart metering applications but there are many others.
Now, Informix is just about the only database that I can think of that supports both operational (transactional) data and stores data in time-series format. There are, of course, a number of data and event warehousing products that support time-series analysis (Netezza and Sensage spring to mind but these certainly aren't the only ones) but they do not natively store time-series data.
Informix, on the other hand, has supported the storage of time-series data since the company acquired Illustra back in the 90s, via what is known as a DataBlade. Previously, these DataBlades (of which there are several) were chargeable extras but now they are bundled with the database.
So, IBM is specifically targeting environments that need to understand time-series. In addition, because Informix also has a spatial DataBlade, the database can also be used where time-series needs to be combined with spatial information. One might also imagine that IBM might also target pure spatial applications with Informix but this is not the intention or, at least, not yet.
The difficulty, of course, is that IBM Netezza supports time-series analytics and also has a strong spatial capability so there is once again an overlap. So the key is to understand that Netezza is targeted specifically at (deep) analytics whereas Informix will be most likely used for instrumented applications where a combination of analytics and operational functions is required. However, IBM will need to set out clearly and explicitly when it will be most suitable to use Informix and when Netezza should be preferred. There are also some differences in approach (ignoring the storage issue for a moment) but we understand that the plan is that these will be brought into line so that, potentially, you might have Informix front-ending onto Netezza.
Leaving aside this issue it is clear that Informix is emerging from under its bushel and this is not just in terms of new marketing directions but also with respect to the product itself. For example, there was the introduction of the flexible grid technology last year and the company is now re-selling 4JS' Genero (which provides modern functionality for Informix 4GL users, as opposed to the late and not lamented Informix NewEra product, which failed to do precisely that). It's good to see Informix back (even though it never really went away).